Time-Optimized Isotope Ratio LC–MS/MS for High-Throughput Quantification of Primary Metabolites

C channel of a metabolite. Applying two optimized LC methods to bacterial cell extracts detected more than 200 metabolites with less than 20% variation between replicates. An exhaustive spike-in experiment with 79 metabolite standards demonstrated the high selectivity of the methods and revealed a few confounding effects such as in-source fragments. Generally, the methods are suited for samples that contain metabolites at final concentrations between 1 nM and 10 μM, and they are sufficiently robust to analyze samples with a high salt content.